# Relationship history for MSHA mine 0503820

Current hierarchy: **Coors William K → Alma American Mining Corp → Fredonia Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Coors William K → Fredonia Mine; 1982-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Terrence C Coburn → Fredonia Mine; 1982-10-01 to 1983-10-20; source msha-controller-operator-history
- **controller_controls_mine:** Terence D  Coburn  et al → Fredonia Mine; 1982-10-01 to 1983-10-20; source msha-controller-operator-history
- **controller_controls_operator:** Terence D  Coburn  et al → Terrence C Coburn; 1982-10-01 to 1983-10-20; source msha-controller-operator-history
- **operator_operates_mine:** Alma American Mining Corp → Fredonia Mine; 1983-10-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Coors William K → Alma American Mining Corp; 1983-10-21 to current/open; source msha-controller-operator-history